Given that Xcelsius is an SAP/Business Objects product (a bit outdated as well) I highly expect there isn't any connectivity between it and TM1
If memory serves I believe you can use an Excel spreadsheet or a CSV file as your data source so you could certainly either take a snapshot of your TM1 cube view or export the cube data into a flat file
Other than that maybe you should have a look at the IBM Cognos product portfolio for a more compatible solution
Olap Objects does (or at least did) offer some connectivity between the two. Visit olapobjects.com, or PM our own Mike Cowie for more details. We use Olap Objects and have found it pretty good though have not had cause to use the Xcelsius integration.